Modelling and simulation of a marine propulsion power plant with seawater desulphurisation scrubber

Abstract

Exhaust gas scrubber is one of the options to comply with the new regulations for sulphur emissions in the shipping industry. This article presents a model-based approach to assess the energy and environmental performance effects from the installation of a seawater flue gas desulphurisation scrubber on a marine two-stroke diesel engine propulsion plant. A mathematical model was built that describes the governing physical and chemical behaviour of the integrated machinery system. The model was used to examine the impact of main scrubber design characteristics on the engine fuel consumption under different engine loads. The results indicate that the desulphurisation system causes an increase in the engine fuel consumption, for constant power output. This is due to the increased back-pressure to the turbocharging system caused by the pressure drops in the desulphurisation system. This effect can be partly mitigated by the installation of forced-draft fans after the desulphurisation system limiting the negative impact on the overall system efficiency to half of its initial value.